It works fine in 3.1c (of cource it get a lot sluggish when recalling presets with great changes in effect loading). In a 21 dsp system with almost all dsp loaded it is rather quick when recalling presets with just parameter differences and not different effect devices. I'll test it soon in 4.0 and 4.5 to see the differences.
The usage is simple: Drop it in project. Save a preset, change values, save again, recall...